1. Field
The present disclosure relates to a tire for a motor vehicle comprising a high contrast pattern comprising a plurality of cavities, it also relates to at least one method for producing such a pattern.
2. Description of Related Art
Tire sidewalls bear a large quantity of patterns intended firstly to provide technical and legal information and secondly to allow consumers to discern the origin of the product.
Attempts are constantly being made at improving the visibility and legibility of these patterns on tire sidewalls.
Document WO2007/045425 describes a high contrast pattern comprising a plurality of strands the cross section of which decreases from the base of each strand toward the tip of the said strand. The density of the strands in the pattern is at least equal to five strands per unit area of pattern expressed in square millimeters (mm2).
The effect of these strands is to “trap” a large amount of incident light radiation falling on the pattern. This allows the pattern to be given a darker appearance by comparison with the rest of the sidewall of the tire. The strands also make it possible to obtain a particularly pleasant feel, of the “velour” type.
However, a pattern comprising such strands may be relatively fragile in the face of certain mechanical attacks, such as rubbing against a pavement. Under the effect of this rubbing, the strands of the pattern may become detached from the tire.
There is therefore a need to propose a high contrast pattern in which the contrast against a sidewall of the tire is more durable.
Definitions
A “tire” means any tire with resilient tread whether or not it is subjected to an internal pressure.
A “tread” of a tire means a quantity of rubbery material delimited by lateral surfaces and by two main surfaces one of which is intended to come into contact with a roadway when the tire is running.
A “bead” of a tire means part of the tire intended to be seated on a wheel rim.
A “sidewall” of a tire means a lateral surface of the tire which is positioned between the tread of the tire and a bead of this tire.
A “pattern” on a sidewall means a collection of openings and intermediate zones separating these openings. The openings are recessed into the sidewall and the intermediate zones are formed by rubbery material.
The “equivalent diameter” of an opening of a cavity or of a base of a protuberance respectively, means the diameter of the circle inscribed inside this opening or in this base, respectively.
A “mold” means a collection of separate mold elements which, when brought relatively close together, are able to delimit a torroidal molding space.
A “marking” in a mold means a plurality of protuberances projecting from this mold and intermediate parts of the mold separating these protuberances.